The transmission of air-borne and impact noise from neighboring spaces through walls and floors in interiors becomes a concerning issue. In cities with high population densities, since many residents live in high-rise concrete buildings, the noise problem is more serious. Impact sounds are an impact or mechanical noises generated by, for example, footsteps, movements of furniture and objects dropped on the floors. Impact sounds are easily generated and transmitted to apartments at lower floors in high-rise concrete buildings through the concrete slab because the above mentioned movements are very common in our daily lives.
The impact sound insulation performance is determined in accordance with ISO 140-6:1998 and ISO 717-2:1997 and its standard test is carried out in accredited laboratory. From the mentioned standard tests, the normalized impact sound pressure level (Lw) is measured and calculated. However, standard rooms with two stories are required and specimen size of at least 10 m2 are required for conducting the standard impact sound insulation test. As such, some researchers have simplified the test for measuring the impact sound. For example, a simple test rig can be set up to conduct a comparable assessment of impact sound insulation performance using a drop tube or tapping machine as impact source.
One of the approaches to improve the impact sound insulation is to increase the thickness of concrete. However, this approach is not effective and causes a larger reduction of space in houses. The other common sound-insulating way is to create a flooring system by adding insulating materials like PVC and thermoplastic tiles above concrete slab. Such flooring system may not stand for long period. Further, such flooring system is likely to degrade in an alkaline and humid environment, especially due to alkaline material in concrete.